Getting in to Southern Newfoundland can basically be done three ways:
Taking Highway 210 southwest from the Trans-Canada Highway Highway 1 at the Goobies Visitor Centre, next to an Irving gas station and Truck, Stop, on the east side of the island
Taking the road southeast from the TransCanada Highway 1 at Barachols Pond Park that leads to Burgeo.
Continuing along the TransCanada east from Port-aux-Basques, ending at Rose Blanche.
Hitchhiking in Southern Newfoundland is not too difficult. Though it can sometimes be a long wait for a ride, as not many cars drive on the key roads e.g. the 210 or the TransCanada if you're trying to get from Rose Blanche to Port-aux-Basques, once you do get picked up there is a good chance that you will get a long ride. People are friendly, and will occasionally go out of their way to drop you off in a convenient location.